My understanding of the shidduch payment is that if the minhag would depend on age as well as location, the payment would vary as well. (No different than any other Sirsur).
It’s certainly possible, but think about it; it would only happen if this program were extremely successful. If we (as a society; I have nothing to do with NASI) can succeed in marrying off hundreds of older girls and preventing igun for so many, wouldn’t it be worth it?